diff options
Diffstat (limited to 'doc/html/H5.format.html')
| -rw-r--r-- | doc/html/H5.format.html | 428 |
1 files changed, 401 insertions, 27 deletions
diff --git a/doc/html/H5.format.html b/doc/html/H5.format.html index 76a9058..ae1ff23 100644 --- a/doc/html/H5.format.html +++ b/doc/html/H5.format.html @@ -104,6 +104,7 @@ TABLE.list TD { border:none; } <li><a href="#NILMessage">Name: NIL</a> <!-- 0x0000 --> <li><a href="#SimpleDataSpace">Name: Simple Dataspace</a> <!-- 0x0001 --> <!-- <li><a href="#DataSpaceMessage">Name: Complex Dataspace</a> --> <!-- 0x0002 --> + <li><a href="#ReservedMessage_0002">Name: Reserved - not assigned yet</a> <!-- 0x0002 --> <li><a href="#DataTypeMessage">Name: Datatype</a> <!-- 0x0003 --> <li><a href="#OldFillValueMessage">Name: Data Storage - Fill Value (Old)</a> <!-- 0x0004 --> <li><a href="#FillValueMessage">Name: Data Storage - Fill Value</a> <!-- 0x0005 --> @@ -119,18 +120,20 @@ TABLE.list TD { border:none; } <ol type=A> <li><a href="#ObjectHeader">Disk Format Level 2a - Data Object Headers</a><i>(Continued)</i> <ol type=1 start=6> - <li><a href="#CompactDataStorageMessage">Name: Data Storage - Compact</a> <!-- 0x0006 --> +<!-- <li><a href="#CompactDataStorageMessage">Name: Data Storage - Compact</a> --> <!-- 0x0006 --> + <li><a href="#ReservedMessage_0006">Name: Reserved - not assigned yet</a> <!-- 0x0006 --> <li><a href="#ExternalFileListMessage">Name: Data Storage - External Data Files</a> <!-- 0x0007 --> <li><a href="#LayoutMessage">Name: Data Storage - Layout</a> <!-- 0x0008 --> <li><a href="#ReservedMessage_0009">Name: Reserved - not assigned yet</a> <!-- 0x0009 --> <li><a href="#ReservedMessage_000A">Name: Reserved - not assigned yet</a> <!-- 0x000a --> - <li><a href="#FilterMessage">Name: Data Storage - Filter Pipeline</a> <!-- 0x000b --> + <li><a href="#FilterMessage">Name: Data Storage - Filter Pipeline</a> <!-- 0x000b --> <li><a href="#AttributeMessage">Name: Attribute</a> <!-- 0x000c --> - <li><a href="#NameMessage">Name: Object Name</a> <!-- 0x000d --> - <li><a href="#ModifiedMessage">Name: Object Modification Date and Time</a> <!-- 0x000e --> - <li><a href="#SharedMessage">Name: Shared Object Message</a> <!-- 0x000f --> + <li><a href="#CommentMessage">Name: Object Comment</a> <!-- 0x000d --> + <li><a href="#OldModifiedMessage">Name: Object Modification Date and Time (Old)</a> <!-- 0x000e --> + <li><a href="#SharedMessage">Name: Shared Object Message</a> <!-- 0x000f --> <li><a href="#ContinuationMessage">Name: Object Header Continuation</a> <!-- 0x0010 --> <li><a href="#SymbolTableMessage">Name: Group Message</a> <!-- 0x0011 --> + <li><a href="#ModifiedMessage">Name: Object Modification Date and Time</a> <!-- 0x0012 --> </ol> <li><a href="#SharedObjectHeader">Disk Format: Level 2b - Shared Data Object Headers</a> <li><a href="#DataStorage">Disk Format: Level 2c - Data Object Data Storage</a> @@ -1620,10 +1623,13 @@ TABLE.list TD { border:none; } first free block (or the <A href="#UndefinedAddress">undefined address</A> if there is no free block). The free block contains "Size of Lengths" bytes that - are the offset of the next free chunk (or the - <A href="#UndefinedAddress">undefined address</A> if this is the - last free chunk) followed by "Size of Lengths" bytes that store - the size of this free chunk. + are the offset of the next free block (or the + value '1' if this is the + last free block) followed by "Size of Lengths" bytes that store + the size of this free block. The size of the free block includes + the space used to store the offset of the next free block and + the of the current block, making the minimum size of a free block + 2 * "Size of Lengths". </P> </td> </tr> @@ -2719,6 +2725,17 @@ TABLE.list TD { border:none; } </center> --> + <hr> + <h4><a name="ReservedMessage_0002">Name: Reserved - Not Assigned Yet</a></h4> + <b>Header Message Type:</b> 0x0002<BR> + <b>Length:</b> N/A<BR> + <b>Status:</b> N/A<BR> + <b>Format of Data:</b> N/A<BR> + + <p><b>Purpose and Description:</b> This message type was skipped during + the initial specification of the file format and may be used in a + future expansion to the format. + <hr> <h4><a name="DataTypeMessage">Name: Datatype</a></h4> @@ -3428,7 +3445,12 @@ TABLE.list TD { border:none; } </tr> <tr> - <td>0-23</td> + <td>0-7</td> + <td>Length of ASCII tag in bytes.</td> + </tr> + + <tr> + <td>8-23</td> <td>Reserved (zero).</td> </tr> </table> @@ -3521,7 +3543,7 @@ TABLE.list TD { border:none; } <div align=center> <table class=format> <caption> - Properties Description for Datatype Version 0 + Properties Description for Datatype Version 1 </caption> <tr> @@ -3649,7 +3671,7 @@ TABLE.list TD { border:none; } <div align=center> <table class=format> <caption> - Properties Description for Datatype Version 1 + Properties Description for Datatype Version 2 </caption> <tr> @@ -4338,7 +4360,8 @@ TABLE.list TD { border:none; } <tr> <td align=center><code>2</code></td> <td>The current version used by the library (version - 1.7.3 or later). In this version, the Size field is + 1.7.3 or later). In this version, the Size and + Fill Value fields are only present if the Fill Value Defined field is set to 1. </td> @@ -4453,7 +4476,9 @@ TABLE.list TD { border:none; } <td>Fill Value</td> <td> <P>The fill value. The bytes of the fill value are interpreted - using the same datatype as for the dataset. + using the same datatype as for the dataset. This field is + not present if the Version field is >1 and the Fill Value + Defined field is set to 0. </P> </td> </tr> @@ -4461,6 +4486,7 @@ TABLE.list TD { border:none; } </div> </P> +<!-- <hr> <h4><a name="CompactDataStorageMessage">Name: Data Storage - Compact</a></h4> @@ -4480,6 +4506,18 @@ TABLE.list TD { border:none; } <P><b>Format of Data:</b> The message data is actually composed of dataset data, so the format will be determined by the dataset format. +--> + + <hr> + <h4><a name="ReservedMessage_0006">Name: Reserved - Not Assigned Yet</a></h4> + <b>Header Message Type:</b> 0x0006<BR> + <b>Length:</b> N/A<BR> + <b>Status:</b> N/A<BR> + <b>Format of Data:</b> N/A<BR> + + <p><b>Purpose and Description:</b> This message type was skipped during + the initial specification of the file format and may be used in a + future expansion to the format. <hr> <h4><a name="ExternalFileListMessage">Name: Data Storage - @@ -4668,7 +4706,7 @@ TABLE.list TD { border:none; } <p><b>Purpose and Description:</b> Data layout describes how the elements of a multi-dimensional array are arranged in the linear - address space of the file. Two types of data layout are + address space of the file. Three types of data layout are supported: <ol> @@ -4688,13 +4726,19 @@ TABLE.list TD { border:none; } the size of the entire array; the size of the entire array can be calculated by traversing the B-tree that stores the chunk addresses. + + <li>The array can be stored in one contiguous block, as part of + this object header message (this is called "compact" storage below). </ol> + + <P>Version 3 of this message re-structured the format into specific + properties that are required for each layout class. <p> <center> <table border cellpadding=4 width="80%"> <caption align=top> - <B>Data Layout Message</B> + <B>Data Layout Message, Versions 1 and 2</B> </caption> <tr align=center> @@ -4730,6 +4774,18 @@ TABLE.list TD { border:none; } <tr align=center> <td colspan=4>...</td> </tr> + + <tr align=center> + <td colspan=4>Compact Data Size (4-bytes)</td> + </tr> + + <tr align=center> + <td colspan=4>Compact Data</td> + </tr> + + <tr align=center> + <td colspan=4>...</td> + </tr> </table> </center> @@ -4743,8 +4799,8 @@ TABLE.list TD { border:none; } <tr valign=top> <td>Version</td> - <td>A version number for the layout message. This - documentation describes version one.</td> + <td>A version number for the layout message. This value can be + either 1 or 2.</td> </tr> <tr valign=top> @@ -4758,8 +4814,10 @@ TABLE.list TD { border:none; } <td>Layout Class</td> <td>The layout class specifies how the other fields of the layout message are to be interpreted. A value of one - indicates contiguous storage while a value of two - indicates chunked storage. Other values will be defined + indicates contiguous storage, a value of two + indicates chunked storage, + while a value of three + indicates compact storage. Other values will be defined in the future.</td> </tr> @@ -4768,7 +4826,10 @@ TABLE.list TD { border:none; } <td>For contiguous storage, this is the address of the first byte of storage. For chunked storage this is the address of the B-tree that is used to look up the addresses of the - chunks.</td> + chunks. This field is not present for compact storage. + If the version for this message is set to 2, the address + may have the "undefined address" value, to indicate that + storage has not yet been allocated for this array.</td> </tr> <tr valign=top> @@ -4777,6 +4838,244 @@ TABLE.list TD { border:none; } size of the array while for chunked storage they define the size of a single chunk.</td> </tr> + + <tr valign=top> + <td>Compact Data Size</td> + <td>This field is only present for compact data storage. + It contains the size of the raw data for the dataset array.</td> + + <tr valign=top> + <td>Compact Data</td> + <td>This field is only present for compact data storage. + It contains the raw data for the dataset array.</td> + </tr> + </table> + </center> + + <p> + <center> + <table border cellpadding=4 width="80%"> + <caption align=top> + <B>Data Layout Message, Version 3</B> + </caption> + + <tr align=center> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + </tr> + + <tr align=center> + <td>Version</td> + <td>Layout Class</td> + </tr> + + <tr align=center> + <td colspan=4>Properties</td> + </tr> + + </table> + </center> + + <p> + <center> + <table align=center width="80%"> + <tr align=left> + <th width="30%"><U><font size=+1>Field Name</font></U></th> + <th><U><font size=+1>Description</font></U></th> + </tr> + + <tr valign=top> + <td>Version</td> + <td>A version number for the layout message. This value can be + either 1, 2 or 3.</td> + </tr> + + <tr valign=top> + <td>Layout Class</td> + <td>The layout class specifies how the other fields of the + layout message are to be interpreted. A value of one + indicates contiguous storage, a value of two + indicates chunked storage, + while a value of three + indicates compact storage.</td> + </tr> + + <tr valign=top> + <td>Properties</td> + <td>This variable-sized field encodes information specific to each + layout class and is described below. If there is no property + information specified for a layout class, the size of this field + is zero bytes.</td> + </tr> + + </table> + </center> + + <P>Class-specific information for contiguous layout (Class 0): + + <p> + <center> + <table border cellpadding=4 width="80%"> + <caption align=top> + <B>Property Descriptions</B> + </caption> + + <tr align=center> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + </tr> + + <tr align=center> + <td colspan=4><br>Address<br><br></td> + </tr> + + <tr align=center> + <td colspan=4><br>Size<br><br></td> + </tr> + </table> + </center> + + <p> + <center> + <table align=center width="80%"> + <tr align=left> + <th width="30%"><U><font size=+1>Field Name</font></U></th> + <th><U><font size=+1>Description</font></U></th> + </tr> + + <tr valign=top> + <td>Address</td> + <td>This is the address of the first byte of raw data storage. + The address may have the "undefined address" value, to indicate + that storage has not yet been allocated for this array.</td> + </tr> + + <tr valign=top> + <td>Size</td> + <td>This field contains the size allocated to store the raw data.</td> + </table> + </center> + + <P>Class-specific information for chunked layout (Class 1): + + <p> + <center> + <table border cellpadding=4 width="80%"> + <caption align=top> + <B>Property Descriptions</B> + </caption> + + <tr align=center> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + </tr> + + <tr align=center> + <td>Dimensionality</td> + </tr> + + <tr align=center> + <td colspan=4><br>Address<br><br></td> + </tr> + + <tr align=center> + <td colspan=4>Dimension 0 (4-bytes)</td> + </tr> + + <tr align=center> + <td colspan=4>Dimension 1 (4-bytes)</td> + </tr> + + <tr align=center> + <td colspan=4>...</td> + </tr> + </table> + </center> + + <p> + <center> + <table align=center width="80%"> + <tr align=left> + <th width="30%"><U><font size=+1>Field Name</font></U></th> + <th><U><font size=+1>Description</font></U></th> + </tr> + + <tr valign=top> + <td>Dimensionality</td> + <td>A chunk has a fixed dimensionality. This field + specifies the number of dimension size fields later in the + message.</td> + </tr> + + <tr valign=top> + <td>Address</td> + <td>This is the address + of the B-tree that is used to look up the addresses of the + chunks. + The address + may have the "undefined address" value, to indicate that + storage has not yet been allocated for this array.</td> + </tr> + + <tr valign=top> + <td>Dimensions</td> + <td>The dimension sizes define the size of a single chunk.</td> + </tr> + </table> + </center> + + <P>Class-specific information for compact layout (Class 2): + + <p> + <center> + <table border cellpadding=4 width="80%"> + <caption align=top> + <B>Property Descriptions</B> + </caption> + + <tr align=center> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + </tr> + + <tr align=center> + <td colspan=2>Size</td> + </tr> + + <tr align=center> + <td colspan=4>Raw Data</td> + </tr> + + <tr align=center> + <td colspan=4>...</td> + </tr> + </table> + </center> + + <p> + <center> + <table align=center width="80%"> + <tr align=left> + <th width="30%"><U><font size=+1>Field Name</font></U></th> + <th><U><font size=+1>Description</font></U></th> + </tr> + + <tr valign=top> + <td>Size</td> + <td>This field contains the size of the raw data for the dataset array.</td> + + <tr valign=top> + <td>Raw Data</td> + <td>This field contains the raw data for the dataset array.</td> + </tr> </table> </center> @@ -5124,14 +5423,14 @@ TABLE.list TD { border:none; } </center> <hr> - <h4><a name="NameMessage">Name: Object Name</a></h4> + <h4><a name="CommentMessage">Name: Object Comment</a></h4> <p><b>Header Message Type:</b> 0x000D<br> <b>Length:</b> varies<br> <b>Status:</b> Optional, may not be repeated. - <p><b>Purpose and Description:</b> The object name or comment is - designed to be a short description of an object. An object name + <p><b>Purpose and Description:</b> The object comment is + designed to be a short description of an object. An object comment is a sequence of non-zero (<code>\0</code>) ASCII characters with no other formatting included by the library. @@ -5150,7 +5449,7 @@ TABLE.list TD { border:none; } </tr> <tr align=center> - <td colspan=4><br>Name<br><br></td> + <td colspan=4><br>Comment<br><br></td> </tr> </table> </center> @@ -5171,7 +5470,7 @@ TABLE.list TD { border:none; } </center> <hr> - <h4><a name="ModifiedMessage">Name: Object Modification Date & Time</a></h4> + <h4><a name="OldModifiedMessage">Name: Object Modification Date & Time (Old)</a></h4> <p><b>Header Message Type:</b> 0x000E<br> <b>Length:</b> fixed<br> @@ -5183,6 +5482,12 @@ TABLE.list TD { border:none; } updated when any object header message changes according to the system clock where the change was posted. + <p>This modification time message is deprecated in favor of the "new" + modification time message (Message Type 0x0012) and is no longer written + to the file in versions of the HDF5 library after the 1.6.0 version. + </p> + + <p> <center> <table border align=center cellpadding=4 width="80%"> @@ -5460,6 +5765,75 @@ where the group name heap is located. </dl> </dl> + <hr> + <h4><a name="ModifiedMessage">Name: Object Modification Date & Time</a></h4> + + <P class=item><B>Header Message Type:</B> 0x0012 + </P> + <P class=item><B>Length:</B> Fixed + </P> + <P class=item><B>Status:</B> Optional, may not be repeated. + </P> + + <P class=item><B>Description:</B> The object modification date + and time is a timestamp which indicates + the last modification of an object. The time is + updated when any object header message changes according to the + system clock where the change was posted. + </P> + + <p> + <center> + <table border align=center cellpadding=4 width="80%"> + <caption align=top> + <b>Modification Time Message</b> + </caption> + + <tr align=center> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + <th width="25%">byte</th> + </tr> + + <tr align=center> + <td colspan=1>Version</td> + <td colspan=3>Reserved</td> + </tr> + + <tr align=center> + <td colspan=4>Seconds After Epoch</td> + </tr> + </table> + </center> + + <p> + <center> + <table align=center width="80%"> + <tr align=left> + <th width="30%"><U><font size=+1>Field Name</font></U></th> + <th><U><font size=+1>Description</font></U></th> + </tr> + + <tr valign=top> + <td>Version</td> + <td>The version number for the message. This document + describes version one of the new modification time message.</td> + </tr> + + <tr valign=top> + <td>Reserved</td> + <td>This field is reserved and should always be zero.</td> + </tr> + + <tr valign=top> + <td>Seconds After Epoch</td> + <td>The number of seconds since 0 hours, 0 + minutes, 0 seconds, January 1, 1970, Coordinated Universal Time. + </tr> + </table> + </center> + <h3><a name="SharedObjectHeader">Disk Format: Level 2b - Shared Data Object Headers</a></h3> <P>In order to share header messages between several dataset objects, object header messages may be placed into the global heap. Since these @@ -5570,7 +5944,7 @@ value with all bits set, i.e. <code>0xffff...ff</code>. <!-- #BeginLibraryItem "/ed_libs/Footer.lbi" --><address> <a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a> <br> -Describes HDF5 Release 1.6.2, February 2004 +Describes HDF5 Release 1.7, the unreleased development branch; working toward HDF5 Release 1.8.0 </address><!-- #EndLibraryItem --><!-- hhmts start --> Last modified: 5 July 2002 <!-- hhmts end --> |